On Fri, Jul 25, 2025 at 4:49 PM Patrick Palka <ppa...@redhat.com> wrote:
> On Fri, 25 Jul 2025, Tomasz Kamiński wrote:
>
> > PR libstdc++/121196
> >
> > libstdc++-v3/ChangeLog:
> >
> > * include/std/inplace_vector (std::erase): Provide default argument
> > for _Up parameter.
> > * testsuite/23_containers/inplace_vector/erasure.cc: Add test for
> > using braces-init-list as arguments to erase_if and use function
> > to verify content of inplace_vector
> > ---
> > I believe the actual fix (adding = _Tp) is trivial and could be commited
> > without review. I have done more extensive changes to tests.
> >
> > Tested on x86_64-linux.
> >
> > libstdc++-v3/include/std/inplace_vector | 2 +-
> > .../23_containers/inplace_vector/erasure.cc | 26 ++++++++++++++++---
> > 2 files changed, 24 insertions(+), 4 deletions(-)
> >
> > diff --git a/libstdc++-v3/include/std/inplace_vector
> b/libstdc++-v3/include/std/inplace_vector
> > index 290cf6eb0e9..b5a81bed3c9 100644
> > --- a/libstdc++-v3/include/std/inplace_vector
> > +++ b/libstdc++-v3/include/std/inplace_vector
> > @@ -1354,7 +1354,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> >
> > - template<typename _Tp, size_t _Nm, typename _Up>
> > + template<typename _Tp, size_t _Nm, typename _Up = _Tp>
> > constexpr size_t
> > erase(inplace_vector<_Tp, _Nm>& __cont, const _Up& __value)
> > {
> > diff --git
> a/libstdc++-v3/testsuite/23_containers/inplace_vector/erasure.cc
> b/libstdc++-v3/testsuite/23_containers/inplace_vector/erasure.cc
> > index c7fda097896..8fb56e90623 100644
> > --- a/libstdc++-v3/testsuite/23_containers/inplace_vector/erasure.cc
> > +++ b/libstdc++-v3/testsuite/23_containers/inplace_vector/erasure.cc
> > @@ -2,18 +2,38 @@
> >
> > #include <inplace_vector>
> > #include <testsuite_hooks.h>
> > +#include <span>
> > +
> > +template<typename T, size_t N>
> > +constexpr bool
> > +eq(const std::inplace_vector<T, N>& l, std::span<const T> r) {
> > + if (l.size() != r.size())
> > + return false;
> > + for (auto i = 0u; i < l.size(); ++i)
> > + if (l[i] != r[i])
> > + return false;
> > + return true;
> > +};
>
> Is this helper function to make the equality checks more concise?
> I like to just use:
>
> ranges::equal(c, (int[]){3, 6, 3});
>
I believe (int[]){...} is compound literal (
https://en.cppreference.com/w/c/language/compound_literal.html)
that is not supported in standard C++. GCC gives me warning on that:
<source>:2:29: warning: ISO C++ forbids compound-literals [-Wpedantic]
In C++ we could use:
> using T = int[];
> ranges::equal(c, T{3, 6, 3});
Or in C++26 this should work, because span can be constructed from
initializer_list:
> ranges::equal(c, std::span{3, 6, 6});
I will try to check that.
I just got this function copied from another test.
>
> which works generally for any range 'c' (of integers). But either
> approach works for me. LGTM either way.
>
> >
> > constexpr void
> > test_erase()
> > {
> > - std::inplace_vector<int, 15> c{1, 2, 3, 4, 5, 6, 5, 4, 3, 2, 1, 4, 4,
> 9};
> > + std::inplace_vector<int, 15> c{1, 0, 3, 4, 5, 6, 5, 4, 3, 0, 1, 4, 4,
> 9};
> > std::erase(c, 4);
> > VERIFY( c.size() == 10 );
> > std::erase(c, 1);
> > VERIFY( c.size() == 8 );
> > std::erase(c, 9);
> > VERIFY( c.size() == 7 );
> > - VERIFY( (c == std::inplace_vector<int, 15>{2, 3, 5, 6, 5, 3, 2}) );
> > + VERIFY( eq(c, {0, 3, 5, 6, 5, 3, 0}) );
> > +
> > + std::erase(c, {});
> > + VERIFY( c.size() == 5 );
> > + VERIFY( eq(c, {3, 5, 6, 5, 3}) );
> > +
> > + std::erase(c, {5});
> > + VERIFY( c.size() == 3 );
> > + VERIFY( eq(c, {3, 6, 3}) );
> >
> > std::inplace_vector<int, 0> e;
> > std::erase(e, 10);
> > @@ -29,7 +49,7 @@ test_erase_if()
> > std::erase_if(c, [](int i) { return i == 4; });
> > VERIFY( c.size() == 8 );
> > std::erase_if(c, [](int i) { return i & 1; });
> > - VERIFY( (c == std::inplace_vector<int, 15>{2, 2}) );
> > + VERIFY( eq(c, {2, 2}) );
> >
> > std::inplace_vector<int, 0> e;
> > std::erase_if(e, [](int i) { return i > 5; });
> > --
> > 2.49.0
> >
> >
